As will be appreciated by those skilled in the art, the need for shields to reduce the glare of the sun on a bright day to ease the effect on a person's eyes has been attempted for eons. It is well known that even primitive Indians and civilizations in the colder and snow covered regions of the world have developed eye shields which comprise simple slits to minimize the amount of light transmitted to the eyes. Likewise, sunglasses are well known as are colored or tinted face masks, shields, and the like.
Further, as is illustrated in U.S. Pat. No. 2,445,153, issued to C. B. Rearick, and U.S. Pat. No. 1,963,716, to I. J. Richey, as well as U.S. Pat. No. 2,138,086, issued to O. Blodjer, the concept of eyeglasses, face shields, or the like which have one transparent section of one color, and another section of a second color is not new in the art. However, a review of these patents, except for the Blodjer patent, disclose rather complex devices for accomplishing this two-colored shield. Also, of course, none of these patents are designed to take the abuse, wear and forces which would be normally experienced by motorcycle riders.
Other patents, such as U.S. Pat. No. 3,748,658, issued to R. W. Albright on July 31, 1973, does show a helmet with a shield having two distinct colors similar to that produced by the process of the present invention. However, upon reading this patent, it is seen that as to the construction of the two-colored shield, there is simply provided information that the shield may be made of a number of plastic materials, and that the light filtering or attenuating may be obtained by tinting, polarization or application of a reflective coating. However, although such techniques may produce a shield which is tinted, for years various agencies have determined that such shields should have minimum physical requirements as to optical clarity, distortion, light transmission capabilities and the like. To this end, to date, there has not been a simple and inexpensive technique for preparing such a two-colored shield during the manufacturing or molding process.
Therefore, it is an object of this invention to provide an inexpensive and simple technique for forming, by injection molding, an optically acceptable transparent face shield which has two distinct portions, one of which at least has a selected color.
Various techniques available for tinting sheets of plastic include the application of a color film on the surface of the face shield, dipping a portion of a shield into a material which will result in tinting and the like. However, as will be appreciated by those skilled in the art, it is most difficult, if not impossible, to laminate a colored film onto a transparent sheet of plastic which will be both flexible and scratch resistant and will possess sufficient optical clarity.
Therefore, it is an object of the present invention to provide a process for the manufacture of an optically transparent device which is both flexible and scratch resistant.
It is another object of this invention to provide a process by which a distinct portion of an optically transparent device may be produced with selected and various colors.